TESTING/LIN/dppt02.f(3)

NAME
TESTING/LIN/dppt02.f

SYNOPSIS

  Functions/Subroutines
subroutine dppt02 (uplo, n, nrhs, a, x, ldx, b, ldb, rwork, resid)
DPPT02

Function/Subroutine Documentation

  subroutine dppt02 (character uplo, integer n, integer nrhs, double precision, dimension( * ) a, double precision, dimension( ldx, * ) x, integer ldx, double precision, dimension( ldb, * ) b, integer ldb, double precision, dimension( * ) rwork, double precision resid)

DPPT02

Purpose:

    !>
    !> DPPT02 computes the residual in the solution of a symmetric system
    !> of linear equations  A*x = b  when packed storage is used for the
    !> coefficient matrix.  The ratio computed is
    !>
    !>    RESID = norm(B - A*X) / ( norm(A) * norm(X) * EPS),
    !>
    !> where EPS is the machine precision.
    !>

Parameters
    UPLO

    !>          UPLO is CHARACTER*1
    !>          Specifies whether the upper or lower triangular part of the
    !>          symmetric matrix A is stored:
    !>          = 'U':  Upper triangular
    !>          = 'L':  Lower triangular
    !>

    N

    !>          N is INTEGER
    !>          The number of rows and columns of the matrix A.  N >= 0.
    !>

    NRHS

    !>          NRHS is INTEGER
    !>          The number of columns of B, the matrix of right hand sides.
    !>          NRHS >= 0.
    !>

    A

    !>          A is DOUBLE PRECISION array, dimension (N*(N+1)/2)
    !>          The original symmetric matrix A, stored as a packed
    !>          triangular matrix.
    !>

    X

    !>          X is DOUBLE PRECISION array, dimension (LDX,NRHS)
    !>          The computed solution vectors for the system of linear
    !>          equations.
    !>

    LDX

    !>          LDX is INTEGER
    !>          The leading dimension of the array X.   LDX >= max(1,N).
    !>

    B

    !>          B is DOUBLE PRECISION array, dimension (LDB,NRHS)
    !>          On entry, the right hand side vectors for the system of
    !>          linear equations.
    !>          On exit, B is overwritten with the difference B - A*X.
    !>

    LDB

    !>          LDB is INTEGER
    !>          The leading dimension of the array B.  LDB >= max(1,N).
    !>

    RWORK

    !>          RWORK is DOUBLE PRECISION array, dimension (N)
    !>

    RESID

    !>          RESID is DOUBLE PRECISION
    !>          The maximum over the number of right hand sides of
    !>          norm(B - A*X) / ( norm(A) * norm(X) * EPS ).
    !>

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 120 of file dppt02.f.

Author

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